Dual feed rate ribbon mounting and transport assembly

ABSTRACT

An assembly for accommodating either carbon or solvent film ribbons includes mechanism couplable to a driver in a machine which is effective to elevate and feed ribbon mounted therein. The mechanism incrementally feeds carbon ribbon at a first constant rate or solvent ribbon at a second constant rate and includes a transport roller for driving the periphery of a flange on a ribbon take-up spool and means for decreasing the angle of rotation of the transport roller as the diameter of wound ribbon on the take-up spool increases to provide a constant feed increment. A feature of the invention resides in the ability to exchange one assembly for another including assembly decoupling means, which serves to prevent unwinding of ribbbon from a supply spool and to maintain ribbon tension so that the assembly may be remounted again to use remaining unused ribbon.

[ 1 Dec.2, 1975 DUAL FEED RATE RIBBON MOUNTING AND TRANSPORT ASSEMBLY [75] Inventor: Hans-Georg Hengelhaupt,

Nuremberg, Germany [73] Assignee: Triumph Werke Nurnherg, A.G.,

Nuremberg, Germany 221 Filed: July 1,1974

21 Appl. No.: 484,621

[30] Foreign Application Priority Data July 21, 1973 Germany 2337191 [52] US. Cl 197/151; 197/175 [51] Int. Cl. B41J 33/36 [58] Field of Search 197/151, 154,160,175; 242/675, 187, 207

[56] References Cited UNITED STATES PATENTS 3,283,876 11/1966 Kern 197/151 3,348,650 10/1967 Meinherz... 197/151 3,349,887 10/1967- Goff 197/151 3,643,777 2/1972 Anderson et al. 197/151 3,677,486 7/1972 Findlay 197/151 3,704,836 12/1972 Yamada 242/187 X OTHER PUBLICATIONS IBM Technical Disclosure Bulletin, Variable Increment Drive, M. A. Henkel, Vol. 7, No. 6, Nov. 1964, p. 526.

IBM Technical Disclosure Bulletin, Ribbon Drive Mechanism, R. E. Lagergren, Vol. 11, No. 2. July 1968, p. 175.

Primary Examiner-Anton O. Oechsle Attorney, Agent, or FirmJoseph R. Spalla; Arthur Gershman [5 7] ABSTRACT An assembly for accommodating either carbon or solvent film ribbons includes mechanism couplable to a driver in a machine which is effective to elevate and feed ribbon mounted therein. The mechanism incrementally feeds carbon ribbon at a first constant rate or solvent ribbon at a second constant rate and includes a transport roller for driving the periphery of a flange on a ribbon take-up spool and means for decreasing the angle of rotation of the transport roller as the diameter of wound ribbon on the take-up spool increases to provide a constant feed increment.

A feature of the invention resides in the ability to exchange one assembly for another including assembly decoupling means, which serves to prevent unwinding of ribbbon from a supply spool and to maintain ribbon tension so that the assembly may be remounted again to use remaining unused ribbon.

6 Claims, 4 Drawing Figures U.S. Patent Dec. 2, 1975 Sheet 1 of 2 U.S. Patent Dec. 2, 1975 Sheet 2 of2 3,923,141

DUAL FEED RATE RIBBON MOUNTING AND TRANSPORT ASSEMBLY The invention relates to ribbon mounting and transport assemblies for carbon or solvent ribbons; more particularly, it relates to assemblies which can be exchangeably mounted according to the type of ribbon required and which are couplable to ribbon elevating and drive means in power-driven typewriters and similar machines; and specifically, to assemblies which include means to transport ribbon in constant predetermined feed increments.

There are disclosed in the prior art drive mechanisms for carbon film ribbons or solvent film ribbons which are intended for one passage only and in which the feed increment is always the same regardless of the diameter of the ribbon coil wound up on the take-up spool whereby such ribbons can be utilized-economically.

It has been suggested in German published applications DT-OS Nos. 1,611,454 and 1,934,271, corresponding to US. Pat. No. 3,604,549, to design a ribbon transporting device, including a ribbon cassette, providing constant incremental feeding of ribbon. As disclosed therein, a pivoting, spring-loaded drive roller, extending into the cassette, is provided with feeding points which bear against the ribbon wound up on the take-up spool. A transport pawl and a transport wheel transmit driving motion to the drive roller through an automatically shiftable gear transmission whose ratio as well as the angle of rotation of the drive roller is constant. The size of the feed increment or the transmission ratio to the drive roller, depending on the type of ribbon used, is determined by means in the cartridge supporting the respective ribbon spools.

Such an assembly is complicated and costly. Furthermore, considering that the drive roller pushes the wound ribbon against the center of the spool, additional tensioning means are required to keep the ribbon extending between spools taut at all times.

In accordance with the present invention, the basic position of a clutch spring, adapted to couple the motion of a driver to a transport roller, is changed relative to the driver thereby varying the angle of rotation of the transport roller according to the respective diameter of the coil of ribbon wound on a take-up spool as determined by a sensing device which is coupled to a control lever. When the assembly mounts a carbon ribbon, the end of the lever is guided by a first cam surface provided in the support plate of the ribbon mechanism, and acts upon a clutch spring positioning lever mounted on the transport roller shaft to thereby set the position of the clutch spring relative to the driver, thus determining the onset of rotation of the transport roller for every forward stroke of the driver.

When the assembly mounts a solvent ribbon, and to achieve maxium utilization of the solvent film ribbon by overlapping the impressions on the ribbon, there is provided on the base plate a manually pivotable, multi armed lever guided by a fixed pin and capable of snapping from one to another detent notch provided in the base plate which acts to rock the control lever, and to establish a second cam or guide surface to control the path of motion of the control lever and, hence, the clutch spring positioning lever thereby determining the onset of rotation of the transport roller so that the impressions overlap on the ribbon in horizontal direction.

When it is desired to change from a film ribbon to a fabric ribbon, the entire film ribbon transport assembly is removed and stored for later use of unused ribbon therein. In removing the film ribbon transport assembly, decoupling means serve to apply a brake to the supply spool and to hold the ribbon between supply and take-up spools under proper tension so that when the assembly is again required the ribbon is properly positioned for mounting.

It is an object of the present invention to provide an assembly for mounting and transporting carbon or solvent film ribbons of the type described which comprises a few parts, functions reliably, is cheap to produce and enables the ribbon spools to be inserted easily. In addition, the feed increment of the transport can be manually shifted to make it adaptable to a required feed increment according to the respective ribbon to be used.

Another object of the invention is to provide a ribbon transport assembly which can accomodate either carbon film or solvent film ribbons which may be exchangeably mounted on a power-driven typewriter to allow use of different ribbons.

Another object of the invention is to provide exchangeably mountable ribbon transport assemblies including transport means which maintains ribbon feed increments constant at a feed rate required for solvent or carbon film ribbons.

Still another object of the invention is in the provision of a transport roller in a ribbon transport assembly, which includes spooled ribbons, whose angle of drive is decreased in proportion to the coil diameter of used ribbon.

A further object of the invention is in the provision of a ribbon transport assembly, which mounts spooled ribbons, that can be removed for replacement yet holds the ribbon against unravelling and under proper tension ready for remounting.

Other objects and many of the attendant advantages of this invention will be readily appreciated as the same becomes better understood by reference to the following detailed description when considered in connection with the accompanying drawing in which like reference numerals designate like or corresponding parts throughout the Figures thereof and wherein:

FIG. 1 is a section (with parts not shown) of a ribbon transport assembly, including ribbon spools, operatively mounted in a machine and showing details of the transport roller clutch springs.

FIG. 2 is a view of a ribbon transport assembly carrying spooled carbon film ribbon looking from the top of FIG. 1;

FIG. 3 is a view, similar to FIG. 2, showing a larger quantity of used carbon ribbon on the take-up spool; and

FIG. 4 is a view, similar to FIG. 2, showing the ribbon transport assembly carrying spooled solvent film ribbon and set to incrementally feed same. ribbon spools Referring now to the drawing and with particular reference to FIG. 1, there is shown a ribbon transport assembly generally designated by reference numeral 11 wherein, as shown in FIG. 2, supply and take-up ribbon spools generally designated respectively by reference numerals 12 and 13 carrying either carbon or solvent film ribbon 14C or 148 are mounted. The spools l2, 13 on which the carbon or solvent film ribbons 14 are .wound comprise a hollow core 15 and a single flange 16, which are mounted as will hereinafter appear in the ribbon transport assembly. The entire ribbon transport assembly 11, as shown in FIG. 1, is adapted to be removably attached by suitable means (not shown) on a machine part 17 which may comprise the movable carriage of a single element typewriter having a single element typehead 18 and removably locked to a pin 19 extending upwardly from the machine part 17 as will hereinafter appear. When so mounted in the operative position, as shown in FIG. 1, a drive pin 21 associated with a part in the machine which oscillates incident to each print action enters between a fork 22 formed on a depending arm of a ribbon vibrator, generally designated by reference numeral 23. With reference to FIGS. 1-3, the vibrator 23 has forwardly extending spaced arms 24, 25, the ends of which are formed with ribbon guide channels 26, 27 which, with the arms 24, 25 and ribbon 14, embrace the type head 18. To achieve maximum utilization of the entire width of film ribbon 14 which is mounted in the assembly 11, the drive pin 21 and vibrator 23 may be variably driven successively through different cyclically repeating angular increments by conventional means to present, for example, three different horizontal levels of a ribbon for printing.

As shown in FIG. 1, the vibrator 23 is pivotally mounted as at 28 on a bracket 31 formed on an assembly support plate 32. An arm 33 on the vibrator 23 extends above the pivot 28 and is coupled as at 34 to a rearwardly extending driver 35 having an extension 36 which extends through an opening 37 in the support plate and is guided by a slot 38 in a bracket 39 on the support plate.

With more particular reference now to FIG. 2, there is shown the assembly 11 mounting a carbon ribbon supply 12 and take-up spools 13. As shown the supply spool core has a larger diameter than the take-up spool core. These spools are mounted, flanged side up, while the assembly 11 is inverted prior to mounting the assembly 11 to the operational position shown in FIG. 1 on corresponding support cores 41 rotatably mounted on pins 42 extending from the support plate 32. Corresponding detent formations (not shown) on the spool and support cores are provided so that spool and support cores rotate as one. The carbon ribbon 14C, intended for one passage only, is led from the supply spool 12, equipped with a brake in the form of a spring 43 wrapped around a reduced portion of support core 41 across a deflector 44- aud the two guides 26, 27 of the ribbon vibrator arms 24, and another deflector 45 to the take-up spool 13 mounted on a support core 41.

The drive train for incrementally feeding the ribbon 14 comprises the vibrator 23 and the driver 35 mounted to the vibrator. With reference to FIGS. 1 and 2, the driver 35 acts upon a leg 46 of a one-way clutch spring 47 surrounding a bushing 48 integraliy formed with a transport roller 51 which is freely rotatable on a support pin 52 fastened in the base plate 32. The clutch spring 47, designed in the form of a coil (FIG. 1) is mounted on the bushing 48 together with a wound one-way clutch spring 53. The spring leg 46, moved by the driver 35, bears against the inner side of the bent down end of shorter arm 54 of a dual-armed clutch spring positioning lever 55 which is rotatably mounted on pin 52 and establishes the starting position of leg 46 of the clutch spring 47 relative to the end of the driver 35; thereafter, the angle of rotation of transport roller 51 is determined as a function or" the instantaneous magnitude of the outside diameter of the coil 57 of ribbon 14C wound up on the take-up core spool 15. The rotary motions of the transport roller 51 are transmitted to the peripheral rim of the take-up spool flange 16 by means of an intermediate roller 58 mounted on arm 49 of a dual-armed lever 61 also pivotally mounted on pin 52.

The freely turning return lock spring 53 wound over the bushing 48 prevents the transport roller 51 from reversing during the return stroke of lever 55, and its free leg 62 is hooked into a notch 63 of a shifting rod 64 in which the leg 62 is retained without backlash by the spring wire 65. The shifting rod 64 is pivotably mounted, as at 66, to a locking lever 67 which, in turn, is pivotably mounted on the base plate 32, as at 68; its inward end carrying a spring 71 which embraces the ends of and influences the brake spring 43 when the locking lever 67 is rotated to release its rightwardly extending end 69 from a groove in locking pin 19 to permit withdrawal and removal of the assembly 11.

Also pivotably mounted on pin 52 is a single-armed return lever 72 which is loaded by the helical extension spring 73 hooked into the locking lever 67 and which, through a downwardly bent end 74, traps the ends 46 of the clutch spring 47 between itself and the bent down end of short arm 54 of the'lever 55 to effect the return of the clutch spring 47 to its starting position after every completed forward stroke of the driver 35.

A sensing device is provided to control the angle of rotation of the transport roller 51 and, hence, of the take-up spool 13 as a function of the outside diameter of the coil 57 of ribbon 14C wound on this spool 13. The sensing device comprises a sensing arm 75 which is spring loaded by a helical extension spring 76 and is mounted on the pin 77. The arm 75 supports at its free end a sensor pin 78 sliding over the ribbon coil 57. A control lever 79, linked to this sensing arm 75 at 81 is carried along by the latter, and a slider pin 82, guided along a curved path in the form of a cam surface 83 machined into the base plate 32, is attached to the rounded enlarged free end 84 of the control lever 79. At the same time, the pin 82 glides along the longer arm 85 of the lever 55, thereby turning the latter and also the clutch spring 47 counterclockwise.

The operating mode of the carbon ribbon transport mechanism is explained below. As already described, to make sure that the transport step of the ribbon 14 is constant at all times, the driving motion goes from the ribbon vibrator 23 to the driver 35 which pushes the bent leg 46 of the clutch spring 47 with every forward stroke of the vibrator 23; in turn, moving the transport roller 51 by a corresponding angular amount which is determined by the size of the outside diameter of the ribbon coil 57 wound up on the take-up spool 13. As already mentioned, the sensing arm 75 senses the radius to the periphery of the ribbon coil 57 on the takeup spool 13. With increasing ribbon coil 57 diameter on spool 13, the sensing lever arm 75, which tightens the ribbon 14 at the same time, is pivoted clockwise against the force of spring 76, dragging or pulling with it the control lever 79 and the pin 82 as guided on the cam path surface 83. Pin 82, at the same time, slides along the longer end 85 of the lever 55 pivoting it counterclockwise with increasing diameter of the wound-up ribbon 14, thereby repositioning, by means of the shorter leg 54 of lever 55, the clutch spring 47 whose leg 46 moves away more and more from the driver 35 in its basic position, thereby shortening the latters effective stroke length. The angleof rotation of the transport roller 51, and with it also the angle of rotation of the take-up spool 13, is decreased in this manner so that for every stroke the length of ribbon transported is the same regardless of the'outside diameter of the ribbon coil. The impressions on the ribbon 14-are, therefore, equispaced in every horizontal line.

To replace spools and particularly ,a full take-up spool 13 by a new empty spool 13, the intermediate roller 58 is manually swung away from the rim of the takeup spool flange 16 by means of a tab 60 on lever 61. When removing the full take-up spool 13, the sensing arm 75, including the control lever 79, jumps inward into its starting position under the force of the extension spring 76. The round portion 86 of the sensing arm 75 then rests against the support core 41. The pin 78, which is spaced from portion 86 by the width of the take-up spool core 15, is, therefore, out of reach of the spool core so that the empty spool 13 can be put in place unhindered. At the same time, the return lever 72 returns the clutch spring 47 and the lever 55 into their starting positions.

When removing the carbon ribbon assembly to mount, for example a fabric ribbon assembly (not shown), the lock lever 67, which is spring loaded by extension spring 87, is swung counterclockwise. In so doing, the shifting rod 64 is taken along also which turns the transport roller 51 in feed direction by a small amount through the return clutch spring 53 hooked into it. In this case the return clutch spring acts as a feed spring and the clutch spring 47 as a locking spring, and the rotation of the transport roller 51 moves the last impression on the ribbon away from the point of impression to avoid overlaps of the new and the old impressions when the carbon ribbon assembly 11 is replaced. When operating the locking lever 67 to-release the carbon ribbon assembly, the brake spring 43 ends are drawn together and tightened to brake the feed spool 12 in its last phase of motion against unintentional turning to avoid slackening of the ribbon. This tightens the ribbon at the same time.

If a solvent film ribbon is used where close typing with overlapping of the points of impression on the ribbon is desired, the transport step can be reduced to a fraction. As viewed in FIG. 4, a three-armed positioning lever 91 is provided for this purpose mounted on the support plate 32 and influencing the control lever 79. The rest position and the operating position of this lever 91, as shown in FIG. 4, are determined, on the one hand, by a slot 92 provided in the right arm 93 which slides along a guide pin 94 fixed in the base plate; and, on the other hand, by a shoulder pin 95 located in the center of lever 91, which shoulder pin can assume one or the other of two positions in a slot 96 cut of the base plate 32, this being accomplished by means of a wire spring 97; the two positions being either in the right notch 96a when in rest position or in the left notch 96b when in operating position, as shown in FIG. 4. For typing with a solvent film ribbon, the lever arm 101, projecting beyond the edge of the base plate, is swung clockwise until the shoulder pin 95 has snapped into the left notch 96b. This causes the rounded portion 102 of the control lever 79 to rest against the left lever arm 103, along which the rounded portion 102 slides in the further course of events, and the pin 82 of control lever 79 is lifted off its cam surface 83 and rocks lever 55.

The angle of rotation of transport roller 51 is thereby so decreased that the points of impression on the ribbon will overlap. In this case, the transport step amounts to about one-fifth of normal.

The transport roller 51, the intermediate roller 58 and the rim of the take-up spool 13 may be knurled or serrated, or a combination of rubberized friction rollers may be used in their manufacture.

The application of the object of the invention is not restricted to ribbon mechanisms where the ribbon is typed on in three horizontal lines, but is also suited for mechanisms with ribbons to be typed on in a single line only.

What is claimed is:

1. A ribbon support and ribbon feed assembly comprising a support plate,

vibrator means pivotally mounted on said support plate and couplable to an oscillatable drive pin when the assembly is mounted for operation in a typewriter,

a prewound ribbon supply spool and a take-up spool rotatably mounted on said support plate with ribbon extending between spools threaded through said vibrator means,

a rotatable transport roller responsive to the movement of said vibrator means for incrementally rotating said take-up spool,

means for sensing the diameter of wound ribbon on said takeup spool,

means coupled to said sensing means for decreasing the angle through which said rotatable means is rotated by said vibrator means to maintain incremental advance of ribbon through said vibrator constant,

a coiled spring clutch wrapped around said transport roller having an end extending radially therefrom,

means for initially positioning said spring end in the path of and spaced a predetermined distance from said vibrator means, said spring being operable when engaged and driven by said vibrator means to rotate said transport roller an amount determined by the spacing between said spring end and said vibrator means,

said take-up spool having a flange,

and means coupling said transport roller to peripherally drive said spool flange.

2. An assembly as recited in claim 1, including a second clutch spring wrapped about said transport roller for precluding reverse rotation of said transport roller when said first spring end is restored to initial position.

3. An assembly as recited in claim 2,

said means coupled to said sensing means comprising a link having a follower pin,

a cam slot in said support plate for guiding said follower pin,

said pin acting on said means for initially positioning said spring end to increase the distance between said spring end and said vibrator means in response to the sensing of an increased diameter of wound ribbon on said take-up spool by said sensing means.

4. An assembly as recited in claim 2, further comprising lever means to removably lock said assembly on a machine part, a drag spring normally loosely mounted around the supply spool, said lever means having a connection to said drag spring and to said second clutch spring whereby when moved to release said assembly it 6. An assembly as recited in claim 1, including a core mounting said take-up spool, said diameter sensing means comprising a lever pivoted on said support plate, a spring biasing said lever to bring its end into engagement with said take-up spool mounting core, and a pin on the end of said lever spaced from the periphery of the lever by at least the thickness of the take-up spool case. 

1. A ribbon support and ribbon feed assembly comprising a support plate, vibrator means pivotally mounted on said support plate anD couplable to an oscillatable drive pin when the assembly is mounted for operation in a typewriter, a prewound ribbon supply spool and a take-up spool rotatably mounted on said support plate with ribbon extending between spools threaded through said vibrator means, a rotatable transport roller responsive to the movement of said vibrator means for incrementally rotating said take-up spool, means for sensing the diameter of wound ribbon on said take-up spool, means coupled to said sensing means for decreasing the angle through which said rotatable means is rotated by said vibrator means to maintain incremental advance of ribbon through said vibrator constant, a coiled spring clutch wrapped around said transport roller having an end extending radially therefrom, means for initially positioning said spring end in the path of and spaced a predetermined distance from said vibrator means, said spring being operable when engaged and driven by said vibrator means to rotate said transport roller an amount determined by the spacing between said spring end and said vibrator means, said take-up spool having a flange, and means coupling said transport roller to peripherally drive said spool flange.
 2. An assembly as recited in claim 1, including a second clutch spring wrapped about said transport roller for precluding reverse rotation of said transport roller when said first spring end is restored to initial position.
 3. An assembly as recited in claim 2, said means coupled to said sensing means comprising a link having a follower pin, a cam slot in said support plate for guiding said follower pin, said pin acting on said means for initially positioning said spring end to increase the distance between said spring end and said vibrator means in response to the sensing of an increased diameter of wound ribbon on said take-up spool by said sensing means.
 4. An assembly as recited in claim 2, further comprising lever means to removably lock said assembly on a machine part, a drag spring normally loosely mounted around the supply spool, said lever means having a connection to said drag spring and to said second clutch spring whereby when moved to release said assembly it serves to tighten said drag spring and to drive said second spring to rotatably drive said transport roller in a feed direction.
 5. An assembly as recited in claim 3, further including manually operable means for setting the distance between said first spring end and said vibrator means, said manually operable means moving said follower pin away from said cam slot, and itself serving to define a path for guiding said link.
 6. An assembly as recited in claim 1, including a core mounting said take-up spool, said diameter sensing means comprising a lever pivoted on said support plate, a spring biasing said lever to bring its end into engagement with said take-up spool mounting core, and a pin on the end of said lever spaced from the periphery of the lever by at least the thickness of the take-up spool case. 